The Characteristics of Optics polished with a polyurethane pad

mura_gadi (Steve) · #1 25-04-2022, 06:55 PM

"The Characteristics of Optics polished with a polyurethane pad "

Found this and thought it raised some good points about some aspects of polishing. Its not a full on science paper but does raise a few interesting ideas about optical finishes and surface/chemical interactions that were new to me.

Ties a few things together mentioned by Mel Bartels and his experiences of using them, but at a slightly more methodical level..

Ps. Thank you fixed.

Saturnine (Jeff) · #2 25-04-2022, 10:37 PM

Link is not working Steve, or is it just me again.

RAJAH235 · #3 26-04-2022, 03:04 AM

Hmmm, You are correct Jeff.
Link gives a "Secure Connection Failed" message.

Maybe this one will work?

> https://opg.optica.org/oe/fulltext.c...0285&id=165527

bojan · #4 03-05-2022, 09:52 PM

Works for me...
Interesting stuff.

mura_gadi (Steve) · #5 04-05-2022, 05:10 AM

If (big if) I understand the paper correctly...

If the removal rate of 1500/2000 grit is greater than the deposition rate of the chemical layer, you would be better off smoothing to the finest grit possible, until the pads are the next step.

Then the pads to polished out, then the laps and parabolisation work.

You would still create the chem layer in lap polishing, but the P/V catchment area would be smaller prior to commencement.

Chem layers should not be present till after the polishing pad stage. You would be down around 1-2nm on 3-5nm polishing pads and working closer to the substrate after smoothing and flash polish on the pads.

But how to test...

*be interesting to see if coating failures lined up to surface composition, silca/defused and concentrates levels.

By.Jove (Jove) · #6 04-05-2022, 11:58 AM

Lots of things will polish glass, but it comes down to (a) how fast (b) large-scale surface quality (profile, ripples, hills/valleys) (c) small-scale quality (pits, scratches, roughness).

Paper laps were used, at one time. Felt pads, PTFE, wax and more besides pitch.

The best polish is probably from ion-beam machining, in a vacuum chamber. Aries in the Ukraine used that for high-end amateur optics but I guess not anymore.